1. Field of the Invention
This invention relates to a double-lock type connector in which terminals are fixedly secured not only by flexible locking arms provided in terminal accommodating chambers but also by a spacer which is inserted in such a manner as to cross the terminal accommodating chambers.
2. Related Art
In general, in the terminal accommodating chambers of a connector, flexible locking arms (hereinafter referred to as "lances", when applicable) are provided to prevent the removal of the terminals. However, in the case of a miniaturized connector, the lances are limited in dimension, and therefore their terminal holding forces may not be large enough. In this case, in addition to the lances, a terminal locking member is provided to doubly lock the terminals.
An example of the double-lock type connector of this type in which the terminal locking member is set in the terminal accommodating chambers to doubly lock the terminals, has been disclosed, for instance, by Japanese Patent Application (OPI) No. 54677/1989 (the term "OPI" as used herein means an "unexamined application"). The double-lock type connector is as shown in FIGS. 13 through 15. FIG. 13 is an exploded perspective view of a conventional double-lock type connector having a spacer which serves as the terminal locking member, FIG. 14 is a sectional view showing the spacer which is temporarily locked, and FIG. 15 is a sectional view showing the spacer which is finally locked.
A connector housing 51 has terminal accommodating chambers 53 arranged in three layers. Each of the terminal accommodating chambers 53 has a lance 54 which is adapted to primarily lock a terminal 55 (cf. FIGS. 14 and 15). A cavity 57 is formed in the middle of the connector housing 51 in such a manner that it is extended across the terminal accommodating chambers 53 and opened in the upper wall 51a of the connector housing 51. A terminal locking member 61 (hereinafter referred to as "a spacer 61", when applicable) is inserted into the cavity 57. The spacer 61 comprises a top wall 63 and a plurality of leg-walls 62 extended downwardly from the top wall 63. The leg-walls 62 are arranged in alignment with partition walls 58 which separate the terminal accommodating chambers 53 from one another. A plurality of terminal locking fins 64 are extended from the right and left surfaces of the leg-walls 62 so that they are engageable with the terminals 55 inserted into the terminal accommodating chambers 53. The spacer 61 is inserted into the cavity 57 in two steps. In the first step, the spacer 61 is temporarily locked, and in the second step it is finally locked. When the spacer 61 is temporarily locked as shown in FIG. 14 (hereinafter referred to as "a temporary locking state", when applicable), given terminals 55 can be inserted between the leg-walls 62. When, after the insertion of the terminals 55, the spacer 61 is further depressed, the spacer 61 is finally locked as shown in FIG. 15 (hereinafter referred to as "a final locking state", when applicable). That is, with the spacer in the temporary locking state, the lances 54 are engaged with the locking holes 75 (FIG. 13) of the terminals 55; that is, the terminals 55 are primarily locked. With the spacer inn the final locking state, the terminal locking fins 64 are engaged with a pair of locking pieces 76 protruded from each of the terminals 55; that is, the latter 55 are secondarily locked. Thus, the terminals 55 have been doubly locked.
The spacer 61 has a plurality of locking protrusions 65 which are extended from one edge of the top wall 63. When the spacer 61 is in the temporary locking state, the locking protrusions 65, being located along the edge of the opening of the cavity 57, clamp the upper wall 51a of the connector housing 51; and when the spacer 61 is in the final locking state, the locking protrusions 65 are engaged with the inner surface 51a of the upper wall 51a of the connector housing, thus fixedly locking the spacer 61.
The above-described conventional double-lock type connector suffers from the following difficulties: If the insertion of the terminal 55 into the terminal accommodating chamber is incomplete, then the terminal locking fins 64 striking against with the locking pieces 76 of the terminal 55, so that the top wall 63 of the spacer 61 is raised, and accordingly it is impossible to lock the locking protrusions 65 of the spacer 61 to the upper wall of the connector housing 51 along the edge of the opening of the cavity 57. This means that the spacer 61 will not function to properly prevent the removal of the terminals 55, or to permit an easy determination of whether or not the terminals 55 are satisfactorily inserted into the connector housing 51. However, the double-lock type connector is disadvantageous in the following point: In the case where the insertion of at least one of the terminals 55 is unsatisfactory, the spacer 61 is partially raised, but the locking protrusions 65 are engaged with the connector housing 51 in the region where the terminals are correctly inserted. Hence, it is difficult for a visual inspection or an inspection with a checker to accurately detect the states of the inserted terminals.
Once the locking protrusions 65 are engaged with connector housing, then they are made dull. Hence, in using the spacer, it is impossible to smoothly engage the spacer with the connector housing.